Not applicable.
1. Field of Investigation
The present invention pertains to an aircraft wing or lifting airfoil that incorporates trailing edge flaps and ailerons as primary flight control surfaces; and improves the performance of said airfoil.
More particularly, this invention addresses the geometry and camber of the airfoil profile and improves the overall aerodynamic efficiency of the airfoil during its operation by means of relocating the trailing edge devices to predetermined positions.
In general, an airfoil is designed for a particular aircraft and the specific use of that aircraft. In most instances the lift and drag characteristics of any given airfoil can be further optimized using established aerodynamic principles.
2. Description of Prior Art
It is well known and extensively documented that changes in an airfoil""s camber during various phases of flight produce optimal results. It has also been suggested that changing the shape of an airfoil""s trailing edge, or attaching certain devices to it, will effectively alter the camber and increase airfoil efficiency.
An object of the present invention is to provide a new fixed camber, employed by the airfoil for the majority of the time that it is in operation, resulting in a greater lift-to-drag ratio and reduced fuel consumption for normal flight operations.
Accordingly, prior art describes and depicts various devices intended to change the camber of an airfoil in flight. Typical of such devices are those shown in the following patents:
U.S. Pat. No. 4,131,253, Zapel
U.S. Pat. No. 4,725,026, Krafka et al.
U.S. Pat. No. 4,741,503, Anderson et al.
U.S. Pat. No. 4,899,284, Lewis et al.
U.S. Pat. No. 5,740,991, Gleine et al.
U.S. Pat. No. 5,875,998, Gleine et al.
U.S. Pat. No. 6,010,098, Campanile et al.
U.S. Pat. No. 6,045,096, Rinn et al.
U.S. Pat. No. 6,076,775, Bauer
U.S. Pat. No. 4,444,368, Andrews, narrows the re-cambering of the wing to a variable displacement of the aft flap.
U.S. Pat. No. 4,053,124, Cole, changes wing camber utilizing the leading and/or trailing edge devices and a flexible skin panel.
Wing camber changes are necessary and desirable during certain low speed aspects of flight, i.e., Take Off, Approach, Landing; and therefore leading edge devices and trailing edge flaps have been incorporated into the systems and operations of aircraft for decades.
To date the concept of changing an airfoil""s camber during flight solely to produce optimal efficiency has yet to be put to practical use. Lack of practical mechanical designs, reliability, and functional hardware; restricts the use of these devices for aerodynamic, structural, and economic considerations.
An object of the present invention is to utilize all trailing edge devices of an airfoil to obtain maximum efficiency throughout the majority of the flight regime.
U.S. Pat. No. 4,867,396, Wainfan, installs a small fixed flap like device to the trailing edge of an airfoil without consideration of trailing edge flaps; or if trailing edge flaps are a part of the airfoil, without consideration of this device""s effects upon the airfoil with trailing edge flaps deployed.
U.S. Pat. No. 5,265,830, Allen, installs a plate across the span of the trailing edge of an airfoil, and is only applicable to an airfoil having a blunt trailing edge.
U.S. Pat. No. 4,542,868, Boyd, attaches a wedge shaped flap at or near the trailing edge of an airfoil to improve the coefficient of lift and reduce the coefficient of drag. This effectively creates an airfoil having a blunt trailing edge with an increase in pressure drag at all but certain optimal airspeeds.
U.S. Pat. No. 5,088,665, Vijgen, Howard, Bushnell, Holmes, incorporates the attachment of a serrated panel to a lifting surface. While in theory this apparatus may improve lift or drag characteristics of an airfoil, the authors have made no claims regarding fuel efficiency in an aircraft.
An object of the present invention is to increase the coefficient of lift and decrease the coefficient of drag with out attaching any external devices to the trailing edge of the airfoil.
U.S. Pat. No. 5,555,651, Henderson, describes a new configuration of a trailing edge flap for a wing which is effective during trailing edge flap extension only.
U.S. Pat. No. 5,342,004, Bobbitt, redesigns the surface contours of the final flap segment to enhance the performance of the airfoil. Altering surface contours may have undesirable aerodynamic effects and loads on aircraft mechanisms controlling the flap segments.
Replacement of conventional flight control surfaces with re-contoured flight control surfaces has not been accepted or proven in the aerospace community.
An object of the present invention is to change the camber of an airfoil without changing the shape or contour of any component of the airfoil.
U.S. Pat. No. 5,407,153, Kirk et al., mounts winglets on an existing Boeing 727 type airplane and re-rigs some of the wing trailing edge flight control surfaces in order to redistribute wing bending and shear loads and contribute to fuel mileage. In this instance the addition of winglets to the airfoil is the major contributing factor to the airfoil""s improved performance.
In 1996 a Supplemental Type Certificate was issued by the Federal Aviation Administration for a modification to the neutral settings of the inboard and outboard ailerons and aft flap segments on Boeing 727 type aircraft; which is now incorporated into a noise abatement modification for Boeing 727 aircraft. It should be noted that the above two modifications to the Boeing 727 aircraft result in limiting trailing edge flap extension.
An object of the present invention is to provide a mechanical means for an aircraft wing to attain optimal camber for the majority of the time it is in operational use, and yet allow normal operation of the wing leading and trailing edge devices.
The aforementioned prior art, some of which is theoretical and some of which has practical applications, does not provide passive drag reduction and lift improvement utilizing the airfoil and the airfoil""s trailing edge components originally supplied by the aircraft manufacturer. An object of the present invention is to increase airfoil efficiency, or the lift-to-drag ratio, employing existing major components of the aircraft wing to enhance the aerodynamics.
In accordance with the present invention a system of repositioning all wing trailing edge flight control surfaces to a predetermined position in order to obtain an increase in the lift-to-drag ratio, resulting in reduced fuel consumption for any distance flown.
Accordingly, several objects and advantages of the present invention are:
(a) to provide an airfoil with a new fixed camber resulting in a greater lift-to-drag ratio;
(b) to provide an airfoil with increased aerodynamic efficiency without attaching any external devices to the trailing edge of the airfoil;
(c) to provide an airfoil with an optimal camber for the majority of the time it is functioning and not restrict the operation of said airfoil""s flight control surfaces;
(d) to provide an airfoil with means for changing said airfoil""s geometric profile without changing the shape or contour of any component of the airfoil;
(e) to provide an airfoil with significant performance improvement through the use of all trailing edge devices on said airfoil;
(f) to provide an airfoil for an aircraft which gives the aircraft the capability to climb to a higher initial cruising altitude;
(g) to provide an airfoil for an aircraft which gives the aircraft an increased rate of climb;
(h) to provide an airfoil for an aircraft that has superior aerodynamic efficiency while the aircraft is in a cruising mode; and
(i) to provide an airfoil for an aircraft which reduces the quantity of fuel consumed by said aircraft over any given distance flown.
Further objects and advantages are to provide an airfoil with increased lift and reduced drag characteristics that is able to lift an aircraft from a given surface to a higher altitude in any specific time; thus reducing perceptible sound decibel levels in the vicinity of the aircraft""s departure. This airfoil""s aerodynamic efficiency will also reduce total powerplant emissions as a result of the reduction of fuel consumed for a given flight. Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings.